Jack



Dec. 21 1926. 611,703

' c. L. ZABRISKIE JACK 3 Sheets-Sheet 1 Filed Dec. 5 9

INVENTOR 62 I ['kar/esl. Zarelrh 'e wk a W M ATTORNEY accommodate the plunger.

in place and to prevent leakage of the working fluid under the flange 15.

, he reservoir space 13 is closed at the top by annular cap which threads into the upper end of cylindrical casing member 12 and is provided with a central opening-21 to The inner wall of this opening is cut away to provide a bevelled shoulder at 22, cooperating with a screw bushing 23 to retain and compress packing 24. The packing is wedged between the shoulder and the bushing and insures 'firm non-leak, sliding contact with the plunger. The cap 20, bushing 23 and packmg 24 have a guiding and oil wiping function which is more important than their function of preventing leakage since in nor- 'mal operation there is very little internal pressure Within the reservoir.

In the top of the guide cylinder 15 is a screw plug 25 having a central opening 26 afiording an unrestricted or other working fluid from the interior of the guide member to the under surface of the plunger head. The passage 26 extends throu h an upwardly projecting externally threaded boss 27 encircled by radial and cup leather washers 28.and 28", retained in place by a rigid cu shaped expander 29 which p valve at this time are {1150 indicated in dotted is in turn firm y jammed against the washers 28 by nut 30 threaded on the extension bOTIS 27. One of the washers is of greater diameter-than the guide cylinder 15 and the cup washer has the usual flexible portion 31 which is turned upwardly and confined be tween the flange 29 on the washer 28 and the interior wall of the plunger to provide a wiping packing surface of appreciable width to prevent escape of the oil from the hydraulic pressure space, back into the reservoir 13, throu h the sliding joint between cylinders 15 an 16.

The two pump cylinders 35 are formed by boring vertical holes in a lateral extension 36 of the base 10. Plunger pistons 37 work in the cylinders 36, said plungers pass- I ing through bushings 38, which are screwed her. To. connect into the enlarged upper ends of the cylinders and serve to retain and compress packings.

39. Tendency to leak aroundthe piston plungers may be further checked by the use secured to the of cupped flexible washers 40 lower ends of the pistons by screws 41. A rocker bar 42 is fulcrumed midway between the pump cylinders on a stud 43 mounted in an upward projection 44 ofthe base memthe rocker 42 with the pis-. tons, I em lov connecting links 45, the lower ends of -w 1ch are pivotally secured in the p 14 by screw is formed with slot-ted inlet bifurcated upper ends 46 of the'piston rods by pivot pins 46, and the upper ends of the "-links arembifui'cated at 47 to straddle the ends of the rocker bar to which they are pivotally connected as by pivot pins 48.

'- extension 49 'at one end. of the rocker [is passage for the oil seat and carries a valve 57 of brass, steel or some other material which will tightly seat when the valve stem is vertically shifted. The means for lifting the valve to prevent oil from running from the reservoir into the well includes a member having lost motion engagement with the plunger, preterably in the form of a ring 58 on the upper end of stem 56, encircling plunger 16 near the upper end of travel of the lower portion thereof. The ring 58 is adapted to be engaged by radially projecting pins 59 secured to the when t position indicated in dotted lines 51, pins 59 will have picked up the ring 58, shifted the-valve stem 56, closed the valve and cut off oil supply from the reservoir to the ump. The osition of the ring, pins and plunger adjacent its lower end, and

plies both the pump cylinders, a-pair of d1-' verging oil passages 60 of relatively small e plunger is moved to its cl ated cross section lead to the res ective c linders 35. Passages 60 communicate with inlet valve seats 61 below the respective pump cylinders, on which inlet .ball checks 62 normally seat by gravity. It is desirable to provide wires or projections 80 disposed centrally of the passages 60 and anchored in closure plugs 80 at the outlets of the passages, such wires serving as cages for these ball valves to limit the extent to which they are elevated oii'their seats on the intake strokes of the pump pistons. The plugs and wires are readily removable for cleaning purposes.

Oil ducts 63 connect the bottoms of the cylinders 35 with the interior'of the cylindrical guide member 16 converging some-- what toward their discharge ends so that the openings 66 above the outlets of the oil passages 63, these openings being sutficiently narrow to serve as ball retainers preventing ball check valves 67 from being forcefully ejected from their seats during forcing strokes of the pumps. Check valves 67 are of course intended to prevent back'flow of oil from theinterior of the guide cylinder and plunger during suction strokes of the pumps and also to hold the load after it take portion 71 registering with an opening 72 in cage plate .64. Passage 70 is controlled by a needle valve 73 having threaded adjustment in a bushing 74Iwhich'is screwed into the base member; suitable acking 75 being used around the valve. T e valve is point which is predetermined by the manually adjustable by the handle 76 and works against a seat 77 in the passage 70. lVhen the valve is retracted as shown inFig.

J 4, passage 70 is placed in communication with a vertical return be closed before the pump is operated, otherwise there can be nil substantial pressure maintained within the plunger and its guide.

- With the needle valve closed and the pump in operation, oil is sucked from the reservoir through assages'60 and into the pump cylinders on t e intake strokes of the pump pistons. On the expelling strokes of such pistons ball checks 62 prevent back flow to' the reservoir and the oil is ex elled through passages 63 around ball chec s 67 into the interior of the plunger guide. checks 67 preventing any back pressure from the interior of the plunger being transmitted to the pump cylinders. After the lifting plunger has been raised by the hydraulic pressure of the motive fluid therein to the cs1- tion of the pins 59' and the length the valve stem 56, the pins will pickup the ring 58 and close the valve 57 to out ofi the supply of oil to the pump. Each pum Wlll then idly draw a vacuum on the intake stroke and release the same on the forcing stroke and these strokes being correlative til) for the two pumps will balance and there will be substantially 'no load on the pump handle. Practically this" operates a most effective signal to the operato'rthat the jack hasrea'ched the'end of the lift. One advantage of control of the intake is that the phase afiording the above described halahead-vacuum, no-load condition, is obvious.

passage 78 to the With a mechanical sto for the plunger as in the old types of fac s,.tlie operator frequently ,fails to notice the added strain on the handle until the stop has been severely .strained or the plunger blown completely out of the reservoir.

To eflect return of the'plunger to its narmal 'telescop'ed position on the guide, it is merely necessary to manually open the needle valve 76 and the weightof the loador other pressure on the plunger will expel the oil through passages 71, 70, '78 into the reservoir until the lowermost position is reached.

The use of the double acting pump involves no increase in the maximum manual eflort because the additional work is done on the up stroke of'thehandle andlit has the advantagethat it doubles the speed with "which the load may be lifted. I entirely eliminate the possibility of straining the. jack or blowing the lifting. plunger out of the reservoirby doing away with all mechanical plunger checking devices and causing the plunger to automatically cutofi the supply to the umps so; that they draw a vacuum when t determined height; The valve stem 56' may be easily made adjustable in length sothat its height may be predetermined in accord-- ance with the particular work to be done by the jack, but I find that for all ordinary pure plunger has risen to a preposes,-an approximately constant length of valve stem, set for maximum height will answer the purpose. As the valve must be closed tightly, it is highly desirable that there should be vsubstantial yield somewhere between the powerful lifting means and the valve seat and preferably the stem 56 is made in two sections as indicated, with a very still connecting spring 56 between them whereby the valve 57 may be seatedas powerfully as desired without danger of tearing the valve oil the stem or bending ring 58 out of horizontal.

With thelilting plunger in its normal telescoped position. the weight of the ring 58, stem-56 and valve 5'? may rest upon a bevelled stop 57* in the passageway 52, keeping he valve away from itsseat 55, but not preventing'inlet cl oil from the force pump;

IOU

Ill)

or the ring 58 may seat upon pins (not shown) projecting inwardly from the walls of the reservoir, thereby holding the valve in the midway position shown in Fig. 5;

With oil or other working fluid under high pressure on the inside-of the plunger guide and plunger, there are only three possible points where leakage might occur and I in every instance, this possibility is miniv mized by the nature. of the sealing-device used. Leaking of the oil around the lung-' or head 17- is practically prevented y the threaded connection between the head and plunger and-.the'packing l'l; Oil pressure in the top of the plunger above the packings 28 will tend to more firmly force the portion 31 of the upper washer against the wall of the plunger. Furthermore, the plunger and its guide are carefully fitted so that the possibilityof leakage around the outside of the guide member 15 is remote. If the offtake valve 73 and its seat 77 are properly mated, there is little or no chance of oil escaping back to the reservoir. If there should be a slight leakage either past valve 73 or around outside of the guide, the escaping oil 'would be directed back into the reservoir.

Although I have shown an embodiment of the invention which makes use of a single telescoping lifting plunger, it will be obvious that any number of plunger sections telescoping one upon the other, might be 6- predetermined i 0 employed.

I claim:

1. A hydraulic jack, including a hydraulically operated lifting plunger, a pump for forcing working fluid under-the plunger to' the plunger has moved a predetermined distance, said means including a valve controlling the supply of working fluid to the pump and means carried by the plunger operable to close the valve.

3. A hydraulic jack, including an oil reservoir, a hollow plunger guide mounted centrally of the reservoir, a lifting plunger sliding on the guide, a pump for pumping oil from the. reservoir into the hollow plunger guide and under the head of the p for cutting off the oil supply when the plunger has travelled a predetermined distance.

4. A hydraulic jack, including an oilreservoir, a hollow plunger guide mounted cen trally of the reservoir, a lifting plunger sliding on the guide, a pump for pumping oil from the reservoir into the hollow lungunger means glunger forcuttingolf the e plunger has risen to a er guide and under the head of the to effect elevation of the same, an

controlled by the oil supply when t 5. A hydraulic jack, including an oil reservoir, hollow plunger guide mounted centrally of the reservoir, a lifting plunger sliding on the guide, apump for pumping oil from the reservoir into the hollow plunger guide and under the head of the plunger -tively connected to the pistons.

unger to effect elevation ofthe same, and means 8,, wherein the lifting plunger includes to effect elevation of the same, a valve controlling the flow of oil from the reservoir to the pump, operating means for the valve, and means on the plunger engageable .with said operating means to close the valve when the plunger has travelled a predetermined distance. i

6. A hydraulic jack, including an oil reservoir, a hollow plunger guide mounted centrally of the reservoir, a lifting plunger sliding on the guide, a pump for pumping oil from' the reservoir into the hollow plungcr guide and under the head of the plunger to effect elevation of the same, means for cutting off the oil supply automatically when the plunger has travelled a predetermined distance, and separate manually operable means for permittingret-urn of oil to the reservoir.

7. A hydraulic jack, including a base, a hollow member mounted on the base and constituting an oil reservoir, a hollow plunger guide disposed centrally of the reservoir, a lifting plunger sliding on the guide,.means for pumping a liquid lifting medium from the reservoir into the guide under the piston, said means including a pair of cylinders in the base, pistons working in the cylinders, a rocker arm having its opposite, ends opera- 8. A hydraulic jack, including a base, a hollow member mounted on the base and constituting an oil reservoir, a hollow plunger guide disposed centrally of the reservoir, a lifting plunger sliding on the guide,means for pumping a liquid lifting mediumfrom the reservoir into the guide under the piston, said, means including a pair of cylinders in the base, pistons working in the cylinders, a rocker arm having its opposite ends operatively connected to the pistons, said base having diverging passageways therein. leading from the reservoir to the pistons, a single valve controlling both of said passageways and converging passageways-leading from the pump cylinders to the interior of the plunger guide. v

9. A device of the class described in claim means-for controlling the valve.

10. A hydraulicjack, including a base, a hollow member mounted on the base and constituting an oil reservoir, a hollow plunger guide disposed centrally of the reservoir, a lifting plunger sliding on the guide, means for pumping a liquid lifting medium from the reservoir into the guide under the piston, said-means including a pair of cylinders in the base, pistonsworking in the cylinders, a rocker arm'having its opposite ends operatively connected to the pistons, said base having diverging passageways therein leading from the reservoir to the pistons, a single valve controlling both of said passageways aged-converging passageways leading from the pump cylinders to theinteriorot' the plunger guide, a valve stem for the controlling valve, operating means for the stem, and pins on the lifting'plunger engageable with said operating means to close the valve and cut ofi the oil supply to the. pump cylinders when the plunger has risen to a predetermined height.

11. A hydraulic jack, including a base, a hollow member mounted on the base and constituting an oil reservoir, a hollow plunger guide disposedcentrally of the reservoir, a lifting plunger sliding on the guide, means for pumping a liquid lifting medium from the reservoir into the guide under the piston, said means including a pair ofcyiinders in the base, pistons working in the cylinders.

a rocker arm having its opposite ends operatively connected to the pistons, and means for automatically cutting off the supply of oil to the pumps when the lifting plunger has risen to a predetermined height.

12. A hydraulic jack, including 'a .base member having a socket therein and a countersunk portion in the bottom of sa d socket, a cylindrical member fitted into the socket and constituting the outer wall of an oil reservoir, a cylindrical guiding member secured in the countersunk portion otthe socket and constituting the inner wall of said reservoir, a lifting plunger slidable on:

the cylindrical guide, a pump including a pair of pumping cylinders formed in the base, pi tons in said cylinders,a rocker arm having its ends connected to the pistons, said base having diverging one way oil passages therein leading from the reservoir to the pump cylinders and one way converging oil passages therein leading from the pump cylinders to the interior of the guide member.

13. A hydraulic jack, including" a base member having a socket therein countersunk portion in the bottom of said socket, a cylindrical member fitted into the socket and constituting the outer wall of an oil reservoir, a cylindrical guiding member secured in the countersunk portion of the socket and constituting the inner wall of said reservoir, a lifting plunger slidable on the cylindrical guide, a pum including a air of pnmpingcylinders ormed in the ase, pistons in said cylinders, a rocker arm having its ends connected to the pistons, said base having diverging one way oil passages therein leading from the reservoir to the pump cylinders and one way converging oil passages therein leading from the pump cylinders to the interior of the guide memher, and a common valve for controlling the flow of oil from the reservoir to the cylinders through said first mentioned passages.

14. A hydraulic jack, including abase member having a socket therein and a countersunk portion inthe bottom of said and a socket and con'itituting the outer wall of an oilreservoir, a cylindrical guiding member secured in the countersunk portion of the socket and constituting the inner wall of said reservoir, a lifting plunger slidable on the cylindrical guide, a pump including a pair of pumping cylinders formed inthe base, pistons in'said cylinders, a rocker armhavmg its ends connected to the pistons, said base having diverging one way oil pa sages therein leading from the reservoir to the pump cylinders and one wayconverging oil passages therein leading from the pump cylindersto the interior of the guide memher, and manually controlled means for-permitting the return of oil from the inter or of the guide member to the reservoir.

15. A hydraulic jack, including. a base member having a socket therein, and having a central countersink in the bottom of said socket, a cylindrical member secured within the socket and constituting the outer wall of an oil reservoir, a cylindrical plunger guide member secured in the countersunk portion of said ocket and constituting the inner wall of said reservoir, a lifting plunger slidable on the guide, a cage plate secured to the bottom of the countersink within the cylindrical guide member, a pump for delivering oil from the reservoir to the interior of the guide member, including an. oil delivering eluding a pair of pump cylinders. pistons in the cylinders, a rocker bar pivoted adjacent its centre, and connecting rods, operatively connecting the ends of the rocker bar to said pistons, the axes of said pump cyline ders and pistons and the plane of movement of the rocker bar being approximately parallel with the axis of the reservoir and appgoximately perpendicular to a radius there- 0 17. A hydraulic jack, including an oil reservoir, a lifting plunger and two single acting pumps for delivering oil from the reservoir under the plunger, said pumps including a pair of pump cylinders, pistons in the cylinders, a rocker bar pivoted. adjacent its center, and connecting rods, operatively connecting the ends of the rocker bar to said pistons, said pistons including bifurcated upper ends straddling and pivotally connected to the lower ends of the connecting rod, the axes of said pump cylinders and pistons and the plane of movement of the rockerbar being approximately parallel "with the axis of the reservoir and approximately perpendicular to a radius thereof.

18. A hydraulic jack, including an oil reservoir, a lifting plunger and two single acting pumps for delivering oil from the reservoir under the plunger, said pumps -ineluding a pair ofpump cylinders, pistons in the cylinders, a rocker bar pivoted adjacent its center, and connecting rods, operatively connecting the ends of the rocker bar to said pistons, said pistons including bifurcated upper ends straddling and pivotally connected to the lower ends of the connecting rod, said connecting rods including bifurcated upper ends straddling and pivotally connected to the ends of the rocker bar, the axes of said pump cylinders and pistons and the plane of movement of the rocker bar being approximately parallel with the axis of the reservoir and approximately perpendicular to a radius thereof.

19. A hydraulic jack, including a base having a socket therein, a cylindrical member secured within the socket. and constituting the outer wall of an oil reservoir, a concentrically disposed internal cylindrical guide member constituting the inner wall of said reservoir, a lifting plunger sliding on the inner cylindrical member, a pump for delivering oil from the reservoir to the interior of the inner member, under said piston, said base member having oil passages to the pump and from the pump to the socket, ball checks in the discharge ends of said oil passagesand a cage plate in the socket limiting the movement of said ball checks.

20. A, hydraulic jack, including an oil reservoir, hollow relatively extensible cylinder and piston members telescoping one upon the other and adapted to be relatively extended by pumping oil therewithin, a pump for delivering oil from the reservoir to the members, means controllcdby relative movement of said members for cutting off the oil supply to the pump when said members have been relatively extended a predetermined distance. a

. 21. A hydraulic jack, including an oil reservoir, hollow relatively extensible cydinder and piston members telescoping one upon the other and adapted to be relatively extended by pumping oil therewithin, a pump for delivering oil from the reservoir to the members, means controlled by relative movement of said members for rendering the pump inoperative to deliver oil to said members when they have been relatively extended to a predetermined extent.

Signed at N ew York in the county of New York and State of New York this third day of December, A. D. 1924.

CHARLES L. ZABRISKIE. 

